Screened in a cargo container … a film still from The Vase in the Container by Kris Lock and Josephine Sweeney.
Photograph: Courtesy: Whitstable Biennale

In the 1930s there was a genre called seaside surrealism. Such artists as Eileen Agar and Paul Nash beachcombed for strangely shaped driftwood, and Picasso created dream pictures from sand.

Seaside surrealism is back on a sunny day on Whitstable beach. The writer Deborah Levy leans nonchalantly against a sea wall reading her poem Watery Things, newly composed for the Whitstable Biennale. She riffs on a line from TS Eliot’s The Love Song of J Alfred Prufrock (“I have measured out my life with coffee spoons...”) to sensually hymn the sea’s succulent life:

“I have measured out my life with whelks mussels clams oysters winkles and crab but not the scallop which is like eating the human earlobe of a swimmer.”

Not a vegan, then. And she’s come to the right place: Levy is talking next to one of the oyster bars that line this Kent fishing town’s seafront. In the harbour nearby, the pissy smells of fresh and less-than-fresh crustaceans mingle. There’s a video screening in a cargo container at one end of this nautical cove. In the film, by Kris Lock and Josephine Sweeney, the gargantuan Kolyvan Vase escapes St Petersburg’s Hermitage Museum and sails the world in a cargo container just like the one we’re in.

Surrealer and surrealer, said Alice. This year’s edition of the Whitstable art festival is a homage to Levy, named after her novel Swimming Home. At the start of the book, a tense black comedy set on the Riviera, Levy quotes the founder of the surrealist movement, André Breton: “We are all at the mercy of the dream...”

Still from Chalta Hi Gaya, 2017, Salma Ashraf’s film about an isolated British Muslim family. Photograph: Salma Ashraf

After following this seaside trail to find artworks along the shore and in nooks and crannies of the weathered town, I found myself in a dream of crabs with cameras and performance artists stroking goldfish. The maritime setting gives video art a fish-and-chips flavour. A film by Salma Ashraf about an isolated British Muslim family is screening at the back of the tiny Whitstable Museum, a wondrous place that mixes everything from fisherman’s tackle to memorabilia of the local celebrity Peter Cushing. Once you get past the sea-shanty clutter, Ashraf’s images of curtained windows and a dark inner space create the sense of being beleaguered by a hostile environment beyond those fluttering drapes.

For the Whitstable Biennale is not just surreal whimsy. It takes from Levy’s book the idea that home is hard to find, that we’re swimming to a place that may not exist. In very different ways, the vase travelling the seas and Ashraf’s film about everyday Islamophobia are challenges to insularity. Levy reads a poem against Brexit by the Kent shore: “Harry from Halifax loves Matteo from Rome / Astrid from Berlin loves Ed from St Ives...”

The most ambitious meditation on the way people, birds and words live in perpetual migration is a performance by Norway’s Caroline Bergvall staged in the Sea Cadets’ Hall among ensigns and pennants and walls painted navy blue. At first it seems Bergvall is not so much a performance artist as an academic who has brought together a panel of experts to discuss the medieval Persian poem The Conference of the Birds, composed by Attar of Nishapur in the 12th century. It turns out that poems, like birds, move freely around our planet. Chaucer produced his own version of Attar’s work, Parlement of Foules, in the 14th century: but that’s nothing, says poetic ecologist David Wallace, who has charted the constant migrations of medieval verses and tales from Canterbury to Muscovy and beyond. Ornithologist Geoff Sample tells of similar exchanges in the songs of European birds.

Fascinating stuff, but how is this art, exactly? Then it gets a bit weird as the speakers, who include subversive artist Adam Chodzko, start to chat among themselves, forgetting there’s an audience, while electronic music composed by Gavin Bryars fills the air with sublime sounds mutated from medieval chants. Bergvall herself turns from compere to shaman as she chants lines by Attar.

Reality melts, dreams take over, birds chatter as they feast on crabs. This is a biennale with a brain. Even if you don’t chance on its rarest wonders you can always eat oysters and read Levy, or Attar, or Chaucer by the shore.